The present invention relates generally to an emergency vehicle warning system and method and, more particularly, to an emergency vehicle warning system and method utilizing a radio frequency communication link.
Emergency vehicles, such as police patrol cars, ambulances and fire engines, when in an emergency state, travel at a high rate of speed and usually, do so through crowded streets and roadways. The law requires that other motor vehicles immediately give the right-of-way to the emergency vehicle. The driver of the motor vehicle, then, must be aware of the approach of the emergency vehicle within a suitable time to safely allow this right-of-way. In order to alert drivers of motor vehicles the approach of an emergency vehicle in an emergency status, the emergency vehicle relies on sight and sound; eg. flashing lights, sirens and horns.
These methods for alerting drivers to the approach of an emergency vehicle are becoming less effective. Advancements in automobile sound proofing and dampening have diminished the amount of external sound intruding into the passenger compartment of an automobile. Combining those advancements with the increased use of cellular car phones and more powerful car stereo systems employing tape decks and CD's, as well as radios, results in a driver being less aware of a siren or horn of an emergency vehicle. Although automobile design advancements have not impaired the driver's vision, the driver must be looking in the emergency vehicle's general direction to be able to see its flashing lights to become aware that it is an emergency state. This would not necessarily occur in the case of a emergency vehicle located behind, and traveling in the same direction of, a motor vehicle. This is also the case of an emergency vehicle approaching an intersection where the cross traffic approaching that intersection can neither hear not see the emergency vehicle. Without an effective way of communicating the approach of an emergency vehicle in an emergency state there is a heightened risk of collisions and therefore, the safety of the emergency vehicle and its occupants along with other motor vehicles and their occupants is jeopardized.
Previous efforts involving emergency vehicles focused on traffic signal preemption or vehicle location. U.S. Pat. No. 4,914,434 issued to Rodney K. Morgan and Bradley K. Cross on Apr. 3, 1990 teaches a system for transmitting a series of UHF spaced apart messages. The emergency vehicle transmits the signal to preempt the normal operation of traffic signals. This patent was an improvement over prior patents teaching traffic signal preemption devices utilizing radio and optical transmitters. U.S. Pat. No. 3,984,807 issued to Adrian B. Haemmig on Oct. 5, 1976 teaches a system for locating emergency vehicles utilizing a plurality of wayside stations each having a radio transmitter with a unique geographical coding. As the emergency vehicle passes such a station a signal is transmitted to a home base or headquarters advising of the whereabouts of the emergency vehicle.
Patents teaching vehicle collision avoidance systems or devices are based on ultrasonic transmitters (U.S. Pat. No. 5,339,075 issued to Terrill Abst on Aug. 16, 1994 and U.S. Pat. No. 5,235,316 issued to Gregory K. Qualizza on Aug. 10, 1993), permanent magnets embedded in a highway (U.S. Pat. No. 5,369,591 issued to Charles Broxmeyer on Nov. 29, 1994) and road surface friction detectors (U.S. Pat. No. 5,286,099 issued to Yasuhiko Fujita, Toshiaki Arai and Makoto Sato on Feb. 15, 1994. U.S. Pat. No. 5,281,947 issued to Clarence W. Durley and Jerry A. Robinson on Jan. 25, 1994 teaches a vehicle safety sensor and warning system employing Microwave Doppler Radar Shift Technology to detect personnel within a predetermined proximity.
These patents, while generally teaching a system for locating a vehicle or avoiding a collision between vehicles and accidents involving people, do not address or resolve the problem of adequately advising a driver of a motor vehicle of the approach of an emergency vehicle when it is an emergency state to allow the driver to give it the right-of-way and, thereby, assuring its safe and expedient passage while, at the same time, assuring the safety of other motor vehicles in or crossing the emergency vehicle's path.
Accordingly, a need exists for a system to advise the driver of a motor vehicle of the approach of an emergency vehicle in an emergency state in addition to the traditional methods of sight and sound.